Is there a formula for calculating the length of wire that can go on a
reel (spindle) where the reels may have different diameters, hub
diameters, and widths, and the wires may have different diameters?

A right cylinder of radius 'r' (a lift duct) intercepts a plane (the
deck of a hovercraft) at an angle of 30 degrees to the vertical. How
may the resulting ellipse be scribed? - i.e., how do I mark the hole
to be cut in the deck?

What is the 'official' definition of 'edge'? Specifically, is an edge
restricted to the intersection of two non-coplanar faces or do two-
dimensional shapes have edges? I'm also curious about a definition of
'face'. How many faces does a two-dimensional shape have?